<style>
  *,
  *::before,
  *::after {
    padding: 0;
    margin: 0;
    box-sizing: inherit;
  }
  body {
    width: 100vw;
    overflow-x: hidden;
    box-sizing: border-box;
  }
  .box {
    width: 100vw;
    height: 500vh;
    overflow-x: hidden;
    background: linear-gradient(
      55deg,
      #000 0 25%,
      #ffb6ff,
      #b344ff,
      #ae38ff,
      #ffb6ff,
      #ffe3ff,
      #ffb6ff,
      #b344ff,
      #000 75% 100%
    );
  }
  .content {
    width: 100vw;
    height: 100vh;
    font-size: 50px;
    font-weight: bold;
    position: fixed;
    display: flex;
    align-items: center;
    color: #fff;
    background: #000;
    mix-blend-mode: darken;
  }

  .content > span {
    padding: 0 12.5vw;
  }
</style>
<body>
  <div class="box">
    <div class="content">
      <span>
        灵动的 iPhone
        新玩法，迎面而来。重大的安全新功能，为拯救生命而设计。创新的 4800
        万像素主摄，让细节纤毫毕现。更有 iPhone
        芯片中的速度之王，为一切提供强大原动力。
      </span>
    </div>
  </div>
</body>
